Technology & Coding

How the Internet Actually Works

Trace a web request from your keyboard to a server and back, and explain every step that happens in between.

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What you will learn about How the Internet Actually Works

The 7-day sprint
  1. A Network of Networks. The Internet is not one network but a set of independent networks that agree to forward each other's packets using a common protocol family.
  2. Packets, Addresses, And Prefixes. IP delivers small, individually addressed, best-effort packets, and every destination is identified by an address that belongs to a numbered block called a prefix.
  3. DNS, The Distributed Directory. DNS turns names people can remember into addresses machines can route to, using a hierarchy of delegations plus aggressive caching rather than one central list.
  4. How Routes Are Chosen Between Networks. Independently run networks called autonomous systems exchange reachability information with BGP, and the resulting path is the product of business policy as much as geography.
  5. TCP, Where Reliability Lives. TCP runs only on the two end hosts and turns a lossy stream of independent packets into an ordered, reliable, rate-controlled byte stream.
  6. TLS And Why HTTPS Is Trustworthy. TLS wraps a TCP connection in encryption and server authentication so the data survives an attacker who fully controls the network in between.
  7. The Whole Journey, End To End. Every layer you have learned fires in sequence during a single page load, and knowing the order turns vague network problems into a short list of testable suspects.
The 80/20: the 6 concepts that matter most
  • Best-effort packet switching
  • The end-to-end principle
  • Addresses, prefixes, and the naming hierarchy
  • Caching with a time to live
  • Interdomain routing as policy
  • Connections and the handshakes that start them
The core idea, explained like you are 5

The Internet moves data by cutting it into small independently addressed packets that any network can forward without remembering anything, and pushing all the hard work of making that look reliable out to the two machines at the ends.

Then the quiz and the ladder

10 questions that correct you when you are wrong, and beginner, intermediate, advanced levels, each with a practical exercise.

Created Sep 13, 2026. No mistakes have been reported by learners.

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